1. Field of the Invention
The invention in general relates to diagnostic apparatus, and particularly to apparatus which is constantly available for diagnosing a process for possible malfunctions.
2. Description of the Prior Art
The operating condition of various processes must be continuously monitored both from a safety and economic standpoint so as to obtain an early indication of a possible malfunction so that corrective measures may be taken.
Some processes, such as the generation of electricity in a power plant, utilize hundreds of sensors throughout the power plant to obtain on-line indications of operating parameters. A diagnostic system, responsive to the sensor outputs, may be provided at the plant to continuously interpret the sensor readings and provide the plant operator with an indication of the condition of the power plant equipment and to recommend any appropriate action which may be necessary from a safety or economic consideration.
The diagnosis may be performed by a digital computer containing a stored diagnostic program. In a preferred embodiment, recent developments dictate the use of computer programs known as knowledge-based expert systems which are rule-based systems containing a multitude of rules generated as a result of interviewing one or more diagnostic experts relative to a specific piece of equipment. As more information is obtained over a period of time, the program may be modified, if required, by adding, deleting, or modifying rules.
A typical plant may include hundreds of sensors, the output signals of which must be periodically scanned and stored. The scanning frequency for some sensors may be in terms of seconds while for others, may be in terms of minutes. Accordingly, the use of an expert or other diagnostic system with the requirement for an enormous amount of storage becomes prohibitively costly for some plants.
The present invention provides an arrangement whereby such plants may be continuously monitored for abnormal conditions at a fraction of the cost normally required for such operation.